Seal for rotary shafts



E. A. LAPHAM SEAL FOR ROTARY SHAFTS Filed Nov. 19, 1936 fiZZayo/zarn,

Gamma; S

Patented May 3, 1938 PATENT OFFICE sEAI. FOR ROTARY sums Edward A.Iapham, Long Island City, N. Y.

Application November is, 1936, Serial No. 111,716

2 Claims. (Cl. 288-1) My invention consists in new and usefulimprovements in seals for rotary shafts and relates more particularly toseals for use in con- 10 Another object is to provide a metalimpregnated carbon seal member possessing a reduced co-eflicient offriction and a maximum of strength and durability. A seal formed of thismaterial quicl-ily develops a high polish on its running 15 face and inturn polishes the face of the material which it contacts, to such anextent as to prevent leakage of water past the seal when anormalpressure is applied to maintain the two .sealing faces together.

Heretofore, carbon and graphite seals have been employed for variouspurposes but it is to be noted that when carbon and graphite materialsare pressed as a dry substance orin a plastic state, they must be heattreated at high temperatures in order to set the binders. In this heattreating, certain of the binders-and other volatile materials are drivenoff, leaving a porous structure which, when used as a seal, will permitseepage or leakage of liquid through its pores 30 and past the sealingmember. Furthermore, a seal thus constructed has definite limitations asto strengthyand has limited wearing qualities,

and its co-eflicient of friction is a set factor.

I have found that by employing as a seal for the use herein specified, amemberformed of carbon or graphite impregnated with metal, the pores ofthe material are'definitely sealed by the 1 metal, against leakage ofliquid, and this is of particular importance when the seal is used for40 automobile pumps or the like.

A further advantage of my invention. lies in the' fact that certaincompositions of carbon, graphite, or carbon-graphite andmetal, can beproduced which are impervious to antifreeze so- 45 lutions such as usedin internal combustion engines which, inthe past, have, destroyed manypackings.

A still further advantage of my invention is that due to theantifriction qualities and the 50 highly polished surface developed,lubrication of the sealing and bearing faces is unnecessary.

With the above and other objects in view which will appear as thedescriptionproceeds; my invention resides in the novel features hereinset 55 forth, illustrated intheaccompanying drawing and moreparticularly pointed outin the appended claims.

Referring to the drawing, I n

Fig. 1 is a sectional view showing the applica tion of one form of myimproved seal. 5

Fig. 2 is a plan view of the seal shown in Fig. 1.

Fig. 3 is a view in side elevation.

Fig. 4 is a sectional-view showing a second form of seal in a differentapplication.

Fig. 5 is a plan view of the seal shown in Fig. 4, and

Fig. 6 is a view in side elevation thereof.

Referring to Fig. 1, numeral I designates generally the circulating pumpof an internal combustion engine having a rotary shaft 2 carrying at oneend an impeller 3. The impeller in the form shown is mounted on a sleevemember 4 which slidably embraces the hollowed end 5 of the shaft 2 andis closed at one end to engage the end of a, coil spring 6, andterminates at its opposite end in a radially extending flange 1.

Between the flange I and the stationary wall 8 of the pump, I apply oneof my improved metal impregnated carbon seals 9 which fits within arecess I0 in'thc wall 8. This seal is annular in shape as shown in-Fig.2, having a central opening II which closely engages the sleeve 4, theouter face of said seal embracing the flange 1. The spring 6 normallytends to force the sleeve 4 outwardly on the shaft 2, thus causing aconstant pressure engagement between the adjacent faces of the flange land the seal- 9.

Due to the composition of the seal 9, its seal-. ing face acquires ahigh polish after a short use,

thus minimizing frictional resistance and at the same time providing amaximum sealing engagement. As before stated, the pores in the carbonare filled and sealed by the metal with i which it is impregnated, thusprohibiting leakage through the seal member itself. 40

In this form of my invention the seal 9 is preferably held stationarywithin the recess III in the wall 8, sleeve 4' and flange I rotatingwith the shaft 2.

. In Fig. 4 I have shown another form of application of my improved sealwherein the seal rotates and the adjacent sealing surface remainsstationary.

Referring to this figure, l2 represents the rotary member of acirculating pump mounted on a rotating shaft l3 supported in bearings I4and IS. The sealing member l6 of a-similar composition of carbonimpregnated with metal, is mounted on the shaft 12 with its aperture I1closely embracing the shaft. In this particu lar form, the seal isdesigned to accommodate the impeller and-is provided with projectingears l8 which fit in suitable recesses in the impeller and cause theseal to rotate therewith.

A portion of the impeller adjacent one face of the seal is hollowed asat l9 to form a spring chamber which receives the coil spring 20, saidspring being interposed between the wall of the chamber and a springadapter 2| which abuts the face of the seal. The opposite face of theseal rotatably engages the projected annular face 22 of the bearing l5against which it is forced bythe pressure of spring 20, thus maintaininga seal at 'this point.

a n of the material, the strength being determined by the kind of metalused, and the porosity of the carbon. Furthermore, I am able to vary thecoeflicient of friction of the seal by using various metal impregnants.Forexample, a given grade of carbon impregnated with copper will have ahigher co-efiicient of friction than one impregmated with lead.

In the manufacture of the seals forming the basis of my invention, thecarbonaceous material is pressed together with a suitable binder underhigh pressure and then kilned, the latter operation driving off thebinding material of the ingredients and leaving a porous structure. Thisstructure is then impregnated by any suitable vmethod with molten metalintroduced under pressure suflicient to thoroughly fill the pores andform a strengthening network throughout the seal, which not onlyincreases its tensile strength many times, but also increases thewearing qualities of thematerial. Furthermore, depending upon the typeof metal used as the impregnant, the co-eflicient of friction of.theseal may be lowered or increased as desired. While I have shown anddescribed the foregoing applications of my metal impregnated carbonseal, it is to be understood that I do not intend to limit myself tothe-forms shown, they being merely examples of many possible adapta-'tions. What I do intend to cover in the following claims is the use of aseal for circulating pumps or the like, which seal is composed of carbonimpregnated with metal, forming a bearing and sealing surface whichrequires no lubrication and which acquires a highly polished seal a bodyportion composed of compressed car- I -bonaceous material whichhas beenrendered porous as the' result of driving oil'- a substantial portion ofthe binder material during a subsequent heat treatment, said bodyportion being reinforced by impregnating the same with molten metalintroduced under pressure and in sufficient quantity to form astrengthening network throughout.

2. A seal of the class described consisting of a body portion composedof compressed carbonaceous material which has been rendered porous asthe result of driving off a substantial portion of the binder materialduring a subsequent heat treatment, said body portion being reinforcedand rendered impervious to fluids, by filling and sealing the porousstructure thereof with molten metal introduced under pressure and insuflicient quantity to form a strengthening network throughout.

EDWARD A. LAPHAM.

